The ultimate objective of the proposed study is to characterize the effluents from normal human lungs by measuring the effects of age, sex, and race on the compositional variations in expired air from 60 normal healthy individuals. The measurement of these effects requires a careful selection of suitable study subjects, collection and gas chromatographic analysis of expired air samples by means of techniques previously developed at the IIT Research Institute, computerized analysis of gas chromatographic patterns of these samples and generation of a composite compositional profile of normal air. This profile is expected to provide a foundation for the investigative departure into the development of non-invasive techniques for early detection of human lung disorders and the performance of various fundamental biochemical studies.